用于巨磁阻生物传感器检测的模拟前端电路

提出一种用于巨磁阻(GMR)生物传感器检测的模拟前端电路。电路采用电压检测的方法,包括基准电压源,单位增益缓冲器,电荷转移型开关电容采样保持电路,流水线模数转换器四部分;基准电压源用于产生传感器阵列的片内激励电压;传感器阵列的检测输出电压经单位增益缓冲器后,由开关电容采样保持电路进行采样,保持,放大;最后经过流水线模数转换器输出数字码流;芯片采用SMIC 0.18μm 1P6M CMOS厚栅氧工艺实现。测试结果表明,在电源电压3.3 V,20 MHz时钟下测试,整体电路输出信号有效精度达到7.2 bit,功耗33 mW,满足GMR生物传感器的检测要求。

Analog Front-end Circuit for the Detection of GMR Biosensor

For the detection of GMR biosensors,an analog front circuit is presented.By voltage detection,the circuit includes voltage references,unit-gain buffer,charge-transferring sample-and-hold amplifier and pineline ADC.The voltage reference is used to stimulate the sensor array.After buffering by unite-gain buffer,the output detection voltage is sampled,held and amplified by charge-transferring sample-and-hold amplifier.Finally,the pineline ADC outputs the digital code.The circuit is implemented in SMIC 0.18 μm 1P6M CMOS thick gate oxide process.The measurement results show that in 3.3 V power supply,at 20 MHz clock frequency,the ENOB of circuit is 7.2 bit with 33 mW power consumption,meets the requirement for GMR biosensor detection.